Sarick effect

This refers to a form of persuasion wherein a person who wishes to convince a hostile audience about an issue can do so effectively by first arguing against his own idea.
This finds mention in the book "Originals" authored by American psychologist Adam Grant,and is attributed to social scientist Leslie Sarick.
Arguing first against one's own idea ,Grant says,disarms the audience and makes the speaker look more credible in their eyes..It also prevents the audience from seeing the speaker as a motivaterd salesman with biased views,and discourages them from trying to think of additional negatives about the speaker's idea.